Background: This study was designed to evaluate whether plasma asymmetric dimethylarginine (ADMA) has any role in predicting hemodynamic responses in clinically healthy young subjects. ADMA, as an endogenous nitric oxide (NO) synthase inhibitor, has been demonstrated to associate with hypertension and vascular reactivity in experimental but not undoubtedly in physiological settings.
Methods: A total of 199 subjects aged 31.4 years (range 24-39 years) were studied. Plasma ADMA and symmetric dimethylarginine (SDMA) were assessed by isocratic high-pressure liquid chromatography using precolumn derivatization with o-phtaldialdehyde at baseline. Blood pressure (BP) was measured by casual measurements in the beginning of the study and after a follow-up period of 2.45 +/- 0.42 years (range, 1.86-3.19 years). Hemodynamic regulation was assessed by noninvasive methods after a follow-up.
Results: Plasma ADMA had a negative association with resting systemic vascular resistance index (SVRI) (r = -0.23, P < 0.01) and pulse wave velocity (PWV) (r = -0.17, P < 0.05) and positive association with cardiac index (CI) (r = 0.21, P < 0.01) after the follow-up. Plasma ADMA had also negative association with responses of SVRI (r = -0.19, P < 0.01) and positive association with CI (r = 0.25, P < 0.001) in a hemodynamic reactivity test. In a multivariate linear model (R2 = 0.20, P < 0.00001), diastolic BP (R = 0.37, P < 0.00001) and ADMA (R = -0.20, P < 0.01) were significant predictors of SVRI.
Conclusions: These results suggest that plasma ADMA seems to play a role in the regulation of vascular tone in young healthy subjects.